View Full Version : Battery Light
01-03-2008, 06:35 PM
Two days ago my battery light started coming on at low rpms. It would stay off while my rpms were up but then stay on when the rpms were below 2k. I checked my cables and found an old pos cable and replaced it. The neg still looks good. Anyway the problem has persisted until today when my lights dimmed and finally the truck would not start. I threw the battery on the charger while I am at work but I could use some opinions on what to check when I get home. I'm guessing the alternator? I looked at the alt wires and they seem ok as does the belt and belt tension. Should I figure that since the light was going off at higher rpms that the alt wasn't sending enough juice at the lower rpm? My plan is to pick up a new alternator on my way home. Any suggestions or opinions are welcome. Thanks. 1988 Ranger xlt 2.9
Oh one more thing. There is some sort if fuse holder or device in the small wire coming off the negative post. The holder seems old and corroded. What is this and could this be causing my issue? Thanks.
01-03-2008, 06:43 PM
it sounds like the alternator, you can take it out and get it tested for free at autozone or advanced auto, just to make sure. you wernt running extra lights or anything right. if you were your alternator may not be able to keep up with the draw. dont drive too far though, you'll get stranded.
01-03-2008, 06:51 PM
No extra lights just a Sirius radio. I think I have a lifetime alt at autozone... Any ideas on that inline link on the neg cable. I'm thinking of just cutting it out of the line. Thanks.
It's generally a bad idea to disable things you can't identify. It's also a bad idea to assume the manufacturer put extra parts in there just for giggles.
In the particular case at hand, cut out that pigtail and your truck will be D E A D. Because that one grounds the computer. It does not affect the charging system.
Visuals for the charging system can find some problems, but absolutely cannot give a clean bill of health. A LOT of problems are missed. Grab your voltmeter and measure voltages around the charging circuit with the engine idling. If the highest voltage is under 13V (measured right across the alternator), your alternator is bad (fortunately, yours is integral so you don't have to ask if it's the voltage regulator, alternator, or rectifier). If there are voltage drops in the circuit aside from the alternator and battery, that's a problem.
If it's all fine and dandy, replace the battery.
I suspect a blown rectifier from your description.
01-03-2008, 07:28 PM
sounds like makg knows what he is talking about. your sirius radio wont have enough draw to kill your truck while running. to me, your battery seems fine, because you have the problem with the engine running, if your truck ran fine but would not start back up, then i would suspect the battery. by the way, bad idea to remove fusible link, they are there to protect a circuit from overload, if something were to happen with out that in place, it could do a lot more damage.
01-03-2008, 07:37 PM
Never mentioned assuming Ford put something there for S's and giggles. Wondering about removing/replacing the corroded inline link is all. Not suggesting disabling anything either. Just trying to learn. Advice sounds good. I'll pick up the new alt on the way home and drop the old one back under the lifetime warranty. Is that link something I can replace? It's pretty wasted... THANKS to ALL.
01-03-2008, 09:35 PM
Make sure your belt isn't slipping, as it will give the same symptom.
The connector can be replaced with a butt connector, or quick connector both available at your auto parts. I would replace rather than trying to clean up the rusty one. shady
01-03-2008, 09:47 PM
you can probly get it from the dealer for a couple bucks, instead of a universal one from autozone. might as well when your there.
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